Cash alternatives such as payment cards are used in a variety of environments. Payment cards may include various mechanisms for storing and/or transmitting account information. Such mechanisms may include magnetic stripes and/or integrated circuit chips. In the case of cards having magnetic stripes, the card is swiped through a reader when used for a financial transaction, typically causing information relating to the user's account and the transaction to be communicated to a reader, through a payment processing network, and ultimately to the issuer of the card. Magnetic stripes used on payment cards comply with various standards that define such properties as the location of the magnetic stripe on the card and the data formats.
Many people have at least several payment cards from one or more issuers. Because carrying a large number of cards can be inconvenient, devices have been provided that include programmable magnetic stripes. The user can input data from a plurality of payment cards into such devices, thereby obviating the need for carrying the individual payment cards. A device of this type includes one card that takes the place of many. When making a financial transaction with the device, the magnetic stripe on the card within the device is programmed with the data from a particular card selected by the user from a list of payment cards whose data has been stored in the device. That card is swiped through a reader and processed in the same manner as an individual payment card.